Systems for controlling environmental conditions, for example in buildings, are becoming increasingly sophisticated. An environment control system may at once control heating and cooling, monitor air quality, adjust lighting, detect hazardous conditions such as fire, carbon monoxide release, intrusion, and the like. Such environment control systems generally include at least one environment controller, which receives measured environmental values, generally from sensors, and in turn determines set-points or command parameters to be sent to controlled appliances.
The environment controller and the devices under its control (sensors, controlled appliances, etc.) are generally referred to as Environment Control Devices (ECDs). An ECD comprises processing capabilities for processing data received via one or more communication interface and/or generating data transmitted via the one or more communication interface.
An example of controlled appliance consists of a light controller, which has one or more lighting device (e.g. lamps) under its control. The environment controller is capable of switching on or off the lighting device(s), and further adjusting the light intensity of the lighting device(s), by sending commands to the light controller.
When a plurality of lighting devices is present in an area, the environment controller is capable of determining a current average light intensity for the area, receiving a target average light intensity for the area, and adjusting the respective light intensities of the plurality of lighting devices to reach the target average light intensity for the area.
A simple way to proceed is to set the light intensity of each one the plurality of lighting devices to the target average light intensity for the area. However, this simple solution does not take into consideration the current values of the light intensity of each one the plurality of lighting devices. The result may be an abrupt adjustment of some of the current values, which is not comfortable for persons located in the vicinity of a lighting device having its lighting intensity abruptly adjusted. For example, if the current light intensity of a given lighting device is 25% of the maximum light intensity, the current average light intensity of the area is 40% and the target average light intensity of the area is 70%, then the adjustment from 25% to 70% of the light intensity of the given lighting device may be considered uncomfortable by some of the persons close to the given lighting device. A better way to proceed with the adjustments (to preserve the comfort of persons affected by the adjustments) is to take into consideration (in combination) the current values of the light intensities of the lighting devices in the area.
Therefore, there is a need for an environment controller and a method for proportionally adjusting the light intensity of several lighting devices.